Except I just wrote about cottonwoods two weeks ago. And I got all gushy last fall about red and yellow leaves, bereft of chlorophyll but high on leftover yellow carotenoids and red anthocyanins.

So now I gotta come up with something fresh. Besides, Lobo needs a walk.

Lobo’s my dog and life coach. He’s got the teeth of a wolf and the disposition of a vegetarian. He’s got a grin that stretches from here to Winslow and half-way back. He’s my hero, on account of how joyfully he chases ravens on the wing even though he hasn’t got a prayer of catching them. Someday I’ll learn to be half as happy as Lobo is when I pick up the leash or when he catches the scent of fresh cat-doo in the box.

Tom Brossart/Roundup

The cottonwoods have just started to turn on the East Verde. Leaves turn after the tree withdraws green chlorophyll from the leaves, leaving behind carotenoids that turn cottonwood leaves yellow.

So I resolve to take Lobo for a walk along the East Verde River through the pitter-patter of falling leaves and then write about whatever Lobo suggests.

We go swishing off through the downed leaves, as the breezy outriders of winter set loose fresh flurries, each leaf falling in a mad, doomed spiral.

The walnut and ash trees peaked two weeks ago, so their bony fingers and knuckles have started to show through the gaudy over confidence of their fall finery. The sycamores are staggering along right behind, still full of yellow and gold bravado — but it’s started to ring hollow.

The cottonwoods have gone yellow-green, like they’re putting a brave face on liver damage or maybe hanging out too much at the tanning salon. Cottonwoods always let the over-eager sycamores go first, so they can test the waters. Sometimes, though, the stuck-up cottonwoods decide the sycamores just made chromatic fools of themselves and so drop their leaves without ever going all-out yellow. This is starting to look like one of those years, with the green cottonwood leaves fluttering down like ticker tape for the returning troops.

We get past the bed and breakfast next door, where Lobo recently endeared himself to the neighbors by bounding into the middle of a wedding party and begging table scraps from the tipsy dinner guests. Cries of alarm. Tipped over chairs. Not everyone understands wolf humor. Now I leave him on the leash until we reach the forest boundary.

My wife says I should not ever let him off the leash: It’s just asking for trouble. She’s absolutely right, but I can’t do it. Besides, the way he bounds forward and tears down the trail the minute I unclip him invariably makes me happy — a contact high.

So Lobo streaks off down the trail at a speed that would break the heart of a greyhound, happy to the tip of every tri-colored hair on his 90-pound frame. I stand a minute and take in the scenery.

The riot of gold, green and yellow leaves quivers, rustles and floats on every hand, the air so cold and clear it’s making me dizzy. Lurid green grass, psychedelic gold trees, saturated blue sky: I am standing on the doorstep of paradise, taking it all in like a Chihuahua with a T-bone steak. I know such good fortune has its karmic price. I’m probably gonna come back as an Afghan woman after the Marines leave —or maybe a lab rat testing ultra low-calorie diets. But for now, I’m perfectly content standing right here in a windy stretch of luck.

Tom Brossart/Roundup

Lobo takes a dip in the East Verde.

I sit down on the trunk of a tipped over sycamore, toppled by some flood and caught in the crook of a much larger tree. I’m inordinately fond of sycamores, perhaps on account of the sexy white bark — somewhere between a sculptor’s marble and a woman’s arm. Sycamores have been turning yellow, dropping leaves every fall and making a comeback every spring for at least 115 million years — which means dinosaurs used to browse their branches before the silly sots got offed on account of standing under an asteroid.

So now I’m sorting through possible fall-based themes so I can come up with a column of text that will keep Tom’s eye-popping fall color shots from bumping together. Maybe I should write something about the breezy autumn of my life. How about: The bill for spring comes due every autumn? Nah. Cliché. Maybe: Dear leaves — thanks for the oxygen. Nah. Did that last year.

Tom Brossart/Roundup

Fall turns sawtooth maple leaves red.

Lobo emerges suddenly from the manzanita and stands alertly on the trail. He’s got the whole Rin Tin Tin thing going. He’s dripping wet, having plunged into the creek at some point. He’s like an undiscovered supermodel with mud on her face and no clue she’s beautiful.

But he’s got something on his beady little brain. He’s in his pointer pose, all quivery.

A javelina emerges from the brush and stands in the middle of the trail, peering near-sightedly toward Lobo.

“Lobo …” says I in my sternest voice.

Lobo launches himself down the trail.

“Lobo!” I holler in futile admonition.

The javelina dashes back into the underbrush upslope, Lobo in hot pursuit.

I start after them. Much crashing in the brush. But now it’s getting closer.

Lobo emerges from the brush at a dead run. He’s going so fast his tail is falling behind. When he gets to the straight-away, he’s gonna break the sound barrier. I’m very pleased. He’s finally learned to come when called.

An instant later, two big old javelina emerge from the underbrush, every shaggy, rank hair on their slab-of-muscle bodies bristling. They hit the trail and turn without breaking stride, a pair of pissed-off peccaries.

Tom Brossart/Roundup

Fall turns sycamore leaves yellow.

I am immediately reminded of a joke. Two hikers round a trail to find themselves suddenly confronting a 1,000-pound grizzly bear. The monster rears up on his back legs and roars. One of the two hikers drops to his knees, rips open his pack, pulls out a pair of tennis shoes and starts pulling off his hiking boots.

“What the heck are you doing?” asks his companion. “You’ll never outrun that bear.”

“I don’t have to outrun that bear,” said the first hiker, lacing up his tennis shoes. “I just have to outrun you.”

Lobo blasts past me at a full run. He’s going so fast that his slipstream is pulling beautiful gold leaves off the trees. The furious javelina are closing on me fast, little puffs of steam coming out of their flattened snouts.

I turn, leap awkwardly for the sycamore trunk and scramble up into the crook of the tree.

The javelina thunder past the base of the tree, pounding the ground so hard that a little flurry of big, floppy sycamore leaves shakes loose and drops on my head.

I grab a big leaf, studying the veins. Did you know that the shape of a sycamore leaf conforms to the ratio of Fibonacci numbers — a mysteriously recurring numerical sequence that relates mathematically to everything from Pythagorean triangles to the Golden Mean, which determines whether we find human faces attractive?

I look down the now-empty trail. Poor javelina. So demoralizing to chase Lobo. I feel your pain guys.

Another swirl of breeze pulls loose another Disneyesque dance of cottonwood leaves.